The present invention concerns an aircraft windshield. It applies to every type of aircraft and especially to commercial airplanes.
Generally speaking, commercial airplanes are outfitted with a windshield having several panes of glass. The windshield of a cockpit has many functions. It allows the pilots to have a visibility of the outside surroundings and thus be able to control the aircraft in flight, as well as on the ground. It maintains a given pressure inside the cockpit during flight, namely, at altitudes where the outer pressure is greatly different from that which is needed inside the aircraft for the persons on board. It protects the pilot and co-pilot against impacts from birds, stones, or other various types of objects. It may thus be subject to substantial degradation requiring a replacement: thus, it is preferable that the glass panes be secured to the structure of the cockpit in a way such that they are easily replaceable.
The windshield should thus meet various criteria of transparency, resistance to structural loads, to pressure, rigidity and solidity to withstand impacts and degradation while allowing for interchangeability, and this for the service life of the airplane.
There is described in patent application FR 2998865 a windshield 1 as represented in FIG. 1 comprising six glasses (only half of them being represented in FIG. 1), two 2F at the front level, namely, facing respectively the pilot and the co-pilot, two 2L in the side region and two 2R in the rear area, again with respect to the pilots and co-pilots.
As illustrated in the embodiment represented in FIG. 2 (and as also shown by FIGS. 2 to 5 of the cited patent), quite often, in schematic and simplified manner, a glass 2 of a windshield 1 of an aircraft cockpit is composed of three superimposed plies 4 of transparent material. The outer ply 6 in contact with the outside atmosphere presents characteristics which allow it to resist abrasion and especially the movement of the windshield wipers, but does not ensure the mechanical strength of the windshield. That strength is provided by the other two plies 7, 8.
The extremity of the three plies 4 is encircled by a one-piece gasket 10.
The gasket 10 and one or more of the extremities of the three plies 4 are enclosed between a one-piece flange 12 and the structure 14 of the cockpit of the aircraft and more particularly a frame provided for this purpose. The flange 12 is secured to the frame with the aid of an assembly system of the nut/screw 16 or equivalent type.
FIG. 2 shows the bonding between the two front glasses 2F and 2F′ (not represented in FIG. 1) of the windshield. The framing of the glass 2F is adjacent to the framing of the glass 2F′ so as to form an angle allowing the two respective glasses no longer to be located in the same plane, but instead be oriented to face the pilot and the co-pilot, respectively. The framing of the glasses 2F in opaque material forms a nontransparent band 17 between the two glasses 2F and 2F′. As a result, the bond between the two front glasses disturbs the visual access of the pilot and co-pilot to the outer surroundings.
In fact, all the bonds between the glasses 2, namely, between the rear glass 2R and the side glass 2L, between the side glass 2L and the front glass 2F and between the front glasses 2F, 2F′ not only diminish the visibility of the pilots and co-pilots in the outer space, but also provides an impediment to their piloting which increases with the size of the space separating the glasses.